Anti-cN1A Antibodies Are Associated with More Severe Dysphagia in Sporadic Inclusion Body Myositis

Cells. 2021 May 10;10(5):1146. doi: 10.3390/cells10051146.

Abstract

In recent years, an autoantibody directed against the 5'-citosolic nucleotidase1A (cN1A) was identified in the sera of sporadic inclusion body myositis (s-IBM) patients with widely variable sensitivity (33%-76%) and specificity (87%-100%). We assessed the sensitivity/specificity of anti-cN1A antibodies in an Italian cohort of s-IBM patients, searching for a potential correlation with clinical data. We collected clinical data and sera from 62 consecutive s-IBM patients and 62 other inflammatory myopathies patients. Testing for anti-cN1A antibodies was performed using a commercial ELISA. Anti-cN1A antibodies were detected in 23 s-IBM patients, resulting in a sensitivity of 37.1% with a specificity of 96.8%. Positive and negative predictive values were 92.0% and 60.6%, respectively. We did not find significant difference regarding demographic variables, nor quadriceps or finger flexor weakness. Nevertheless, we found that anti-cN1A-positive patients presented significantly lower scores in IBMFRS item 1 (swallowing, p = 0.045) and more frequently reported more severe swallowing problems, expressed as an IBMFRS item 1 score ≤ 2 (p < 0.001). We confirmed the low sensitivity and high specificity of anti-cN1A Ab in s-IBM patients with a high positive predictive value. The presence of anti-CN1A antibodies identified patients with a greater risk of more severe dysphagia.

Keywords: anti-cN1A antibodies; autoantibodies; inclusion body myositis; inflammatory myopathies.

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • Aged
  • Autoantibodies / chemistry*
  • Biopsy
  • Deglutition Disorders / metabolism*
  • Female
  • Humans
  • Immunosuppressive Agents
  • Inflammation
  • Italy / epidemiology
  • Male
  • Middle Aged
  • Muscle Weakness
  • Muscle, Skeletal
  • Myositis, Inclusion Body / immunology*
  • Myositis, Inclusion Body / metabolism
  • Predictive Value of Tests
  • Prevalence
  • Sensitivity and Specificity

Substances

  • Autoantibodies
  • Immunosuppressive Agents